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Tropical Storm Irwin Discussion Number   8
NWS National Hurricane Center Miami FL       EP102023
1100 AM HST Mon Aug 28 2023
 
Deep convection has been fading away, and Irwin is getting closer to 
becoming a post-tropical cyclone.  Satellite imagery suggests 
mid-level dry air is wrapping around much of circulation and an area 
of decaying convection remains over the northern portion of storm.  
The initial intensity remains at 35 kt based on recent ASCAT passes.
 
Irwin has yet to make its much anticipated westward turn and is 
still moving west-northwestward at 9 kt.  Still, model guidance 
insists the cyclone will go to the west shortly and remains tightly 
clustered.  The general westward motion, with a increase in forward 
speed, is expected to continue through the forecast period.  The 
latest track forecast has shifted to the north and lies between the 
previous forecast and the simple consensus aids.
 
The storm appears to be in the process of weakening.  The extent of 
tropical-storm-force winds in the northeast quadrant has decreased 
significantly based on the satellite-derived surface wind data. Sea 
surface temperatures and mid-level relative humidities are expected 
to decrease along the forecast track and Irwin is expect weaken 
further in the next day or so.  The storm is still forecast to 
become a remnant low within 48 hours, though this could happen 
sooner.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  28/2100Z 18.6N 124.2W   35 KT  40 MPH
 12H  29/0600Z 19.0N 126.3W   30 KT  35 MPH
 24H  29/1800Z 19.0N 129.0W   30 KT  35 MPH
 36H  30/0600Z 18.9N 131.7W   30 KT  35 MPH
 48H  30/1800Z 19.0N 134.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 60H  31/0600Z 19.0N 136.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  31/1800Z 19.2N 137.7W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  01/1800Z 19.3N 140.2W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  02/1800Z 19.2N 142.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Bucci
 
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